Sry if this is confusing but when I was playing Pokémon (I don’t usually)
But I came across a Pokémon called ditto who called shape-shift sooo like here’s the idea: 
Type:oddballs
Rarity: common, legendary or mythical (or boss)
Catchphrase: can turn in to anything!
Description: in a field a bromon was sitting peacefully, but then a blast of energy hit the bromon! After that, the bromon was never quite the same because it could shape-shift into different bromons. After that, it was known as the shapeshifter.
PS: it can be a boss or a bromon